Siemens Aktiengesellschaft

Klaus-Robert Hauschildt

Wolfgang Kleeberg

Heinz Hacker

Klaus Kretzschmar

Wolfgang Rogler

Helmut Markert

Klaus Kretzschman

Electrically insulating composite materials formed from (1) epoxy resins and (2) polymeric fiber reinforcement which have high strength are formed if the cross-linking of the epoxy resin is accomplished by anionic polymerization using tertiary amines of the formula ##STR1## as catalyst.

Method for manufacturing electrical insulating composite materials

This invention relates to a method for the manufacture of molded material for an insulating component made of a quick-hardening reaction resin which employs a hardening catalyst. An object of the invention is to provide reaction resins which allow the manufacture of molded materials with increased dimensional heat resistance and at the same time, good mechanical properties. According to the invention, a reaction resin mixture of a polyepoxide and a polyisocyanate (EP/IC resin) with a formula mole ratio EP:IC of about 1 to 5 and a viscosity of up to about 7000 mPa.multidot.sec (at 25.degree. C.) is cross-linked under pressure by means of a tertiary amine or imidazole hardening catalyst at a gelling temperature of about 130.degree. to 150.degree. C. and is post-hardened at a temperature of 150.degree. to 200.degree. C. This produces a reaction resin molded material (OX/ICR molding material) containing oxazolidinone and isocyanurate rings with a mole ratio OX:ICR greater than 1 and, after hardening, the reaction of the epoxy and isocyanate groups of the EP/IC resin, is above about 90%.

Method for the manufacture of molded materials

This application relates to methods for the manufacture of leakage current-proof epoxy-resin molded materials from epoxy resin mixture based on di- or polycarboxylic-acid glycidyl esters, di- or polyfunctional cycloaliphatic olefinic epoxides and dicarboxylic-acid anhydrides, carried out in such a manner that molded materials with good mechanical properties are obtained also for parts of large volume. For this purpose, the invention provides that, by means of the experimentally determined time necessary to reach the maximum temperature during the cross-linking of the epoxy resin mixture under quasi adiabatic conditions, the rate of cross-linking of the epoxy resin mixture is adjusted, by the addition of a diol or polyol, to at least as long as the time necessary to reach the maximum temperature during cross-linking of the glycidyl ester/dicarboxylic acid anhydride components.

Method for manufacturing epoxy resin molded materials

This invention provides reaction resin molded materials (OX/ICR molded materials) containing oxazolidinone and isocyanurate rings prepared from reaction resin mixtures of polyepoxides and polyisocyanates (EP/IC resins) in the presence of a hardening catalyst and has as an object to provide a simple manufacturing method for heat resistant OX/ICR molded materials with improved mechanical properties. According to this invention, EP/IC resins which are capable of casting and impregnating and which are free from solvents are provided. These resins have a formula mole ratio of EP:IC of about 1 to 5 and a viscosity of up to 7,000 mPa sec at 25.degree. C. and are cross-linked by means of tertiary amine or imidazole hardening catalysts at gelling temperatures of up to 130.degree. C. and post-hardening temperatures of 130.degree. to 200.degree. C. to produce OX/ICR molded materials with a mole ratio OX:ICR greater than 1, wherein the reaction of the epoxy and isocyanate groups is above 90% after the hardening.

Method for the manufacture of reaction resin molding materials

Molding materials, laminates, stratified material and cover or protective layers which are of high electrical and mechanical quality are formed from polymerisable epoxy compounds if the corss-linking of the epoxy resins is accomplished by anionic polymerisation, using mixed catalysts of tertiary amines of the formula: ##STR1## and an imidazoles of the formula: ##STR2## as a polymerisation catalysts.

Method for the manufacture of epoxy resin molding materials

The invention provides epoxy resin casting compounds based on polyepoxides, polycarboxylic acids and/or polycarboxylic acid anhydrides with directly or latently present carboxyl functions, which can be converted by polyaddition and/or polymerization into insoluble and unmeltable cross-linked polymers. According to the invention, the carboxyl functions are replaced, at least partially, by maleic acid monoallyl ester and a polymerization-initiating radical former, the maleic acid monoallyl ester component being present in the reaction mixture in free form and/or in the form of adducts to the polyepoxide. The epoxy resin casting compounds constitute systems which can be processed in a wide temperature range and are cross-linked rapidly at elevated temperature.

Growing community of inventors

Nuremberg, Germany

Klaus-Robert Hauschildt